Currently, a physical network can be virtualized by using network virtualization over layer 3 (NVO3) technology, so that a same physical network can be shared by different tenants, traffic of the tenants can be isolated, and Internet Protocol (IP) addresses of the tenants can be overlapped. Each tenant usually can use one or more virtual networks. Customer edges (CE) in each virtual network communicate with each other by using a layer 2 network, and CEs of different virtual subnets communicate with each other by using a layer 3 network.
In an NVO3 network, a remote network virtualization edge (NVE) usually learns, by using a control plane, a media access control (MAC) address of a CE that is connected to a local NVE. The Ethernet virtual private network (EVPN) protocol runs between NVEs. Each NVE learns a MAC address of a locally connected CE by using a data plane. The local NVE may notify the remote NVE of the locally learned MAC address of the CE by using the Border Gateway Protocol (BGP). After learning, from an NVO3 network side, the MAC address of the CE sent by the local NVE, the remote NVE establishes a correspondence between the MAC address and an interface in a MAC forwarding table. For a multihomed CE, that is, a CE that simultaneously accesses multiple local NVEs, the remote NVE needs to enable a MAC address of the CE to separately correspond to multiple interfaces. However, when the remote NVE is a virtual switch (vSwitch), this load sharing manner is not supported in many cases. In addition, when a local NVE accessed by the CE changes, for example, a fault occurs in an access link between the CE and the local NVE, the remote NVE needs to modify the correspondence between the MAC address of the CE and the interface in the MAC forwarding table. When there is a large quantity of remote NVEs, a burden of modifying the MAC forwarding table is heavy, and network scalability is seriously affected.